Normalize/brighten prior to de-click

[weskola]

There are some processes that bring out clicks that are normally inaudible prior to that process. Normalizing will do this. The Virtual Valve Amplifier will do this. From my experiences it seems that any process that brightens or excites the higher frequencies will do this. For this reason, I wait to do my final, manual de-clicking after running any of these processes.

I've read some postings on the web regarding this and I have done a lot of experimenting. Right now, I will always normalize about 90-95% prior to my de-clicking. For me, it catches many more clicks. I have also read where some people will run a reverse RIAA curve prior to declicking and then restoring the RIAA curve when done. I have also tried this and, while it appears to work to some extent, I feel that I am losing something when I restore the RIAA.

In an earlier posting on this forum, there was reference to the fact that some people run a pre-emphasis curve (Para EQ) prior to running the INF and then running the appropriate de-emphasis curve afterward. I would think this is similar to running the reverse RIAA but not quite as drastic. This thread was called "Impulse Filter" and it's last posting was 8/10/2000.

Has anyone tried any of these things? In particular, I am curious about the pre-emphasis curve.

[Dan McDonald]

Re: Normalize/brighten prior to de-click

Hi Weskola -

I've noticed a similar problem in that, if you begin with something of very low quality (such as a mid-60s cassette recording) and brighten it up so that it sounds better, you hear a lot of noise that you couldn't hear before. The thing still sounds better, even with the noise, but you really hear the limitations of the original recording. I haven't found any way around this.

Dan

[Craig Maier]

Re: Normalize/brighten prior to de-click

There is a very interesting psyco-acoustical effect that noise has on the human ear. If you take a dull recording (with very little top end, say over about 4 to 5 KHz) and then add white noise to the program, everyone will say that there is more "top end" or better highs. But the fact of the matter is that the amplification of the high end of the spectrum of the source material has not been impacted by this process at all. The ear hears something beyond the 4 to 5 KHz range, and even though it is just noise, it is perceived as having better highs. So, when you over-emphasize noisey old cassette recordings, you could simply be playing into this human factor of fooling your hearing, since tape hiss is not dramatically unlike white or pink noise. You can experiment on your own to proove this to yourself. Use the Random Noise generator in Diamond Cut to create a noise file. Add that file to a completely dead musical performance and adjust the gain of the noise. You shall hear what I am referring to.

[Peter Allen]

Re: Normalize/brighten prior to de-click

Hang on, this thread has gone off-topic. Weskola didn't say he wanted to brighten his recording to improve the perceived sound. As I understand it, he asked about the best use of pre-emphasis before declicking to improve declicking performance. This was to be followed by reverse de-emphasis to exactly restore the original recording's frequency balance.

I too am interested in any comments on this.

Peter

[weskola]

Re: Normalize/brighten prior to de-click

Mr. Allen is correct in that I am looking for some feedback on the use of the pre-emphasis curve prior to declicking. I am not using this to brighten or enhance the final sound of my WAV file. At this point it is solely to bring out the clicks a little more. The Virtual Valve Amplifier will handle the enhancement later. I am simply interested in finding out if anyone else has done anything like this.

Lately, I have experimented quite a bit in this area. I have started to use the 78uSec Pre-emphasis curve prior to declicking. When previewing this filter on a segment of the WAV file, there is a noticeable difference. Many more clicks become audible. The difference is not just "perceived". I know what I hear. I will then normalize to about 90-95% and declick. After declicking I will run the 78uSec De-emphasis curve. Normalize again to 95% and run the continuous noise filter. The Virtual Valve Amplifier is then applied to give me the brightness and clarity that I am looking for. Normalize again to 95% and then listen to the WAV file to perform my final, manual declicking.

While this is a process that I have now totally adopted as my routine, I'm still interested in feedback. What may be the pros and cons of this routine?

[Beautman]

Re: Normalize/brighten prior to de-click

Why all the normalizing?

[Craig Maier]

Re: Normalize/brighten prior to de-click

While we provided the pre-emphasis and de-emphasis curves to be used for various applications, I have no personal experience with its use in the manner you describe with the Impulse filter. But, if it works for you, it is very hard to argue with success, right? When I get some spare time, I will experiment with it myself and then make more comment on it.

[weskola]

Re: Normalize/brighten prior to de-click

I do the normalizing because the application of various filters can change the peak level. I have also found that normalizing can sometimes bring out a barely audible click.

I have had many occasions whereby I would perform my manual click removal and then normalize prior to transfer to CD. When I listened to the CD on the way to work I would occasionally hear a click where there shouldn't be one. I would go back to the pre-normalized, manually-declicked WAV file and listen to the area with the click. Usually, there was no click or, if there was one, it was so barely audible that you would have to listen very carefully in order to hear it. I would then listen to the normalized file and discover that this barely audible click had been given some "life".

It is for this reason that I will enhance, sweeten and normalize my files prior to the final, manual declicking.